Cadence Support Gem Doesn't Work

I'm playing warrior. I tried this gem on both leap slam as well as perfect strike. Nothing happens, no attack speed difference. I kept the gem stat window open during use to be sure. I don't attack fast enough for it to disable, so not sure if that part works. But it definitely doesn't do what it says.

Definitely doesn´t work at all.

yep still doesn't work with leap slam.....